This invention relates to golf balls, and, more particularly, to a golf ball which has dimples which are evenly and uniformly distributed so that the ball has six axes of symmetry.
For maximum consistency and accuracy, golf ball dimples should be evenly and uniformly distributed, with many axes of symmetry and without bald patches or dimple-free areas. However, the existence of a mold parting line resulting from molding the golf ball cover has traditionally limited the number of axes of symmetry to three or less. Recent attempts to increase this number by introducing multiple false parting lines have yielded patterns with large bald patches. For example, U.S. Pat. No. 4,142,727 describes a golf ball in which the spherical surface of the ball is divided into twelve areas corresponding to the faces of a regular dodecahedron. The surface includes from 12 to 30 rectangular bald patches or dimple-free areas. The patent also refers to dividing the surface of the ball into areas corresponding to an octahedron or an icosahedron. In each case, however, from 12 to 30 bald patches will be present.
U.S Pat. No. 4,141,559 describes a dimple pattern which generates an icosahedral lattice of equilateral spherical triangles, each triangle containing an equal number of dimples. However, this patent specifically states in column 4, lines 56-61 that "all circumferential pathways of substantial width (0.005 inch or greater) that may be circumscribed about the ball (except that at the flash line [parting line], which is the equator of the ball) will interest [sic: should be "intersect"] several of the depressions." In other words, the only circumferential pathway or great circle path which does not intersect dimples is the mold parting line.
British Patent No. 1,381,897 describes with respect to FIGS. 10-13 a dimple pattern formed by dividing the surface into the twenty triangles of an icosahedron and filling the triangles with dimples at points where great circle paths intersect. The dimples at the mold parting line are adjusted so that no dimples fall on the parting line.